1. Field of the Invention
The present invention relates to a percussion detecting apparatus for detecting a vibration of a pad being struck and outputting a detection signal for production of a musical tone.
2. Description of the Related Art
Conventionally, there has been known an electronic drum or other electronic percussion instrument that produces a musical tone based on a detection signal from a percussion detecting apparatus having a sensor for detecting a vibration of a pad being struck at its percussion surface. A percussion detecting apparatus of this type generally has a drum-shaped pad member supported by a support frame.
For example, a musical instrument disclosed in Japanese Laid-open Patent Publication No. 6-175651 has a main body made of hard rubber and formed into a shallow dish shape, a base plate formed by an iron plate and disposed at a bottom of the main body, and a base on which the main body and the base plate are supported. A pad plate embedded in a pad rubber having a percussion surface is supported by the base plate via a doughnut-shaped cushion member, a pad sensor is fixed to a back surface of the pad plate, and a rim sensor is fixed to an inner periphery of a rim plate embedded in a periphery of the main body of the musical instrument.
When a player strikes the pad, the pad plate vibrates and a vibration of the pad plate is detected by the pad sensor. When the player strikes the rim to play a rimshot, the rim plate vibrates and a vibration of the rim plate is detected by the rim sensor.
Since the pad plate is not in direct contact with the rim, but in contact with the rim via the pad rubber made of rubber softer than the rubber constituting the rim, a vibration conveyed from the rim is attenuated by the pad rubber and is not conveyed to the pad sensor. Each of the pad sensor and the rim sensor detects a vibration in the form of electrical signal, which is amplified by an amplifier and sounded as a musical tone by a speaker.
In another musical instrument disclosed in Japanese Laid-open Patent Publication No. 2002-169546, a pad member, a percussion detecting sensor, and a sensor support are supported via a disk-shaped thin-film elastic member by an upper case (case member) so as to float from the upper case.
Specifically, the sensor support mounted with the percussion detecting sensor is coupled, together with the thin-film elastic member, to the pad member via a bridge member. The thin-film elastic member made of synthetic resin having elasticity and hard to convey a vibration is formed into a disk shape having a thickened portion and a thin-film portion disposed radially outwardly of the thickened portion. The thin-film portion is sandwiched and fixed between a stay of a light-emitting unit and the upper case. When the pad member is in an unstruck state, the pad member, the sensor, and the sensor support are coupled via only the thin-film portion of the elastic member to the upper case so as to float from the upper case, i.e., made independent from the upper case in respect of vibration transmission. As a result, a vibration transmitted from the case member is substantially intercepted at the thin film portion, so that transmission of the vibration to the sensor is effectively suppressed, thereby preventing noise from occurring, which would be otherwise caused when another pad or the case member is struck.
In the musical instrument disclosed in Japanese Laid-open Patent Publication No. 6-175651, an external vibration other than a vibration of the pad member (e.g., a vibration of the floor or a vibration caused when another pad or the case member is struck) is sometimes conveyed to the base. In that case, the external vibration is absorbed by the cushion member, if the vibration is a vertical vibration. However, a micro-vibration having a small amplitude is not effectively absorbed by the cushion member and detected by the pad sensor (if the sensor is highly sensitive), which poses a problem that the detected micro-vibration provides a disturbance in the production of a musical tone (so-called noise intrusion).
In addition, since a motion of the pad plate is restricted by the rim and hence a lateral vibration cannot be absorbed, the lateral vibration is detected by the pad sensor and sometimes provides a disturbance.
With the musical instrument disclosed in Japanese Laid-open Patent Publication No. 2002-169546, a vibration transmitted from, e.g., the floor to the upper case constituting a part of the support frame is absorbed, if the vibration is a vertical vibration, by the thin-film portion of the elastic member. On the other hand, since the thin-film portion is formed to laterally extend in a plane, a lateral vibration is hardly absorbed by the thin-film portion and is sometimes detected by the sensor, resulting in occurrence of disturbance.